The use of radiation to treat medical conditions comprises a known area of prior art endeavor. For example, radiation therapy comprises an important component of many treatment plans for reducing or eliminating unwanted tumors. Unfortunately, applied radiation does not discriminate between unwanted materials and adjacent tissues, organs, or the like that are desired or even critical to continued survival of the patient. As a result, radiation is ordinarily applied in a carefully administered manner to at least attempt to restrict the radiation to a given target volume.
This has led, for example, to the use of collimators to attempt to restrict the profile of the radiation beam in a way that avoids untargeted tissue to the sides of the targeted area. Unfortunately, this practice does not address the entire problem space. As one example in these regards, the radiation beam must typically pass through untargeted tissue on the journey to the targeted area.
Many treatment plans provide for exposing the target volume to radiation from a number of different directions. Arc therapy, for example, comprises one such approach. This approach not only permits radiating the target from a variety of different angles, it also helps to avoid radiating any specific non-targeted portion of the patient's body for the entire treatment period. Though truly beneficial, this approach alone may not be necessarily optimum for all application settings. When treating a target that is adjacent to particularly sensitive non-targeted portions of the patient's body, for example, even this reduced level of exposure may be a cause for concern.
Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. Certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. The terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.